Leukemia in Cats, Kittens

Feline Leukemia is a cancer of the cat's lymphocytes (white blood cells). It is caused by the Feline Leukemia Virus and is a common cause of illness and death in cats. Feline Leukemia can be transmitted from cat to cat via bodily fluids, primarily saliva. The presence of the virus can be detected via blood tests. Prevention often involves proper vaccination.

Hi Simba - I recently found an adorable kitten & am already in love with it.

Yesterday I took it in for its first vet visit. The vet said
it tested positive for feline leukemia(!) however we would test
again in 3 weeks to be sure.

I am not going to have the kitten put down no matter what the
test shows. Please tell me more about Feline Leukemia so we know what to do.

Dear Donna G,
How wonderful you have taken this little gal into your home. She
is lucky to have a caring person as you to watch our for her.
Here is a little background on Feline Leukemia (FeLV)

As you know, FeLV is a common cause of illness and death among
cats.

WHAT IS FELINE LEUKEMIA (FeLV)

Feline Leukemia is a disease caused by the Feline Leukemia Virus
(FeLV). The Leukemia itself is a cancer of the cat's
lymphocytes (white blood cells). What FeLV does is it produces an
enzyme which permits it to make and insert copies of its genes
into cells it infects. When it infects the white blood cells it
suppresses the immune system.

HOW DO CATS GET FeLV?

Contact with bodily fluids from an infected Cat. Examples of
transmission are contact with saliva from mutual grooming,
biting, milk, urine, feces...In some cases contact with an
infected cat's food dishes (not as common).

The good news is that FeLV is not stable in that does not live
long outside of the body...a few hours maybe in a normal
house.

Infected mother cats usually pass on the virus to their kittens,
which often results in early death or even abortion.

Note that not all cats exposed to FeLV become infected with the
virus since some cats may not be exposed to sufficient quantities
of the virus and / or they are able to defend themselves via an
effective immune response that eliminates the virus.

Age is also important. The younger the kitten the more
susceptible he/she is to getting sick.

FELINE LEUKEMIA SYMPTOMS AND PROGNOSIS

FeLV is a very common cause of cancer
when it infects the blood cells (see above) and it also causes
blood disorders that adversely affect the immune system...Cats
with weak immune systems (see FIV) are
susceptible to infections that they would otherwise easily
resist.

Anemia is another common cause of death in FeLV kitties, (affects
nearly 25% of infected cats). What happens is that the red blood
cell in the bone marrow or in the blood stream becomes infected
by FeLV which causes depletion and anemia.

Unfortunately, nearly 90% of infected cats die within 3 to 3 1/2
years after diagnosis. About half of deaths are caused by immune
system suppression in which an otherwise beatable infection
kills. Signs to watch (though not exclusive to Leukemia) for
include:

WHAT ARE THE STAGES OF FELINE LEUKEMIA

There are 2 stages in FeLV infection.

First State / Primary viremia is an early stage of
infection. This is when the cat's immune system fights FeLV.
If successful, an effective immune response will eliminate the
virus from the bloodstream and stop the disease from reaching
State 2

Stage 2 / Secondary viremia is a later stage where the
cat has a persistent infection of the bone marrow and other
internal tissue. When the cat is in stage 2 it is no longer able
to eliminate the virus and will be infected for the rest of its
life.

Diagnosis of FeLV infection is straightforward, as the virus is
present in the blood and within infected cells in the blood, bone
marrow and elsewhere in the body. The tests (there are two)
detect a protein component of FeLV as it circulates in the
bloodstream

IS THERE A VACCINE FOR FELINE LEUKEMIA?

There is now an widely used vaccine for preventing Feline
Leukemia. There is both an injectable and a needle-less version
of the feline leukemia vaccine. Note that there have been
instances where the vaccine has resulted in injection-site
tumors. Please discuss with your vet.

If your cat has been infected with FeLV the onset of symptoms
will depend on the strength of his /her immune system. Your best
bet is to continue being the loving and supportive parent and to
keep the cat away from uninfected cats. - Simba

Leukemia in a New Family Kitten

Dear Simba - My family and I just got a 6 week-old kitten last night. We took it to the vet today to get it checked out and they ran a blood test. From the blood test we found that the kitten may have
leukemia, we will not know for sure until Monday.

My question is what do we do next if the kitten has this problem.
We are totally new to the cat world and are trying to learn as we
go. From people I have talked to this test is somewhat
unreliable. I have been told that if the kitten has leukemia it
still will live a long life. If this is true what do we need to
do to keep as health as possible? I have a 4 and 2 year old that
are getting attached quick and the less pain for everyone the
better, that's including the kitty too. Kevin W

Dear Kevin W,
I certainly hope that as I write this your little kitten is free
and clear of Feline Leukemia. If he is not, do not give up just
yet. Although he is against the odds, your little friend may make
it after all. Given your young children and your wish to avoid
causing them undue pain, you may want to give the kitten to a
foster care home where the little guy can be cared for. There are
many loving folks out there that will open their hearts to
needy kittens, if only for a short time. Keep me posted.
Simba

Surviving Feline Leukemia: Sheba's Story

Dear Simba,
I read the letters on FLV and wanted to add something. I'm
glad you urged your readers to wait and see if their cats are
okay. My cat Sheba caught FLV at an early age. Sheba was a year
old when we found her. She is now close to her 9th birthday! Over
the years, we've had only minor problems with FeLV - Sheba
had one mouth wound that required surgery to heal, and 2 decaying
back teeth required removal. That's it! We've been very
lucky, and I'm so glad that I listened to my heart and did
not put Sheba to sleep when we learned she was FLV+. I want to
encourage fellow cat lovers to give FeLV+ cats a chance! Do not
put your cats 'to sleep' unless s/he is in severe pain or
discomfort. Thanks for letting me share Sheba's story!
Michelle in Houston

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